Multi-channel audio and digital theatre in general is becoming more common. Digital media is more frequently being presented in places where many different viewers or listeners may come and go, where viewers and listeners move around, or where theatre or room configurations frequently change.
FIG. 1 shows a system 50 rendering audio/video media in an area 52. Area 52 may be a room, a region in a room, a home or public theatre, and so on. System 50 may be a computer, a set-top box, a satellite receiver, a gaming device, a personal video recorder, a DVD player, or any other type of device that renders, displays, projects, or transmits audio and/or video data. System 50 may receive audio/video data over a network 54, or it may play audio/video data from a local storage unit 56. The audio/video data may be in a format such as MPEG-2 format, WMV, or WMV-HD, or any other form of stored, streaming, or broadcast media.
Media devices may render media in a variety of ways. For example, system 50 has a splitter 58 that parses or splits audio/video content into two streams; a compressed video stream and an audio stream. A video decompressor 60 decompresses the video stream and passes it to a video renderer 62 that generates frames to display on display 64. An audio playback device or module 66 generates an audio signal played by speakers 68. Playback module 66 and video renderer 62 may be devices such as video cards, audio cards, or other forms of hardware. They may also be realized with software. Plug-ins 70 can be included to provide added or necessary media rendering functionality. Spatial or temporal video filters and audio special effects filters are examples of rendering plug-ins.
Of interest in FIG. 1 is ‘audio sweet’ spot 72. An audio sweet spot is a region or position within a listening area where the audio content will have the highest quality, that is, where the audio will have the optimal sound or where the audio will most realistically and accurately reproduce the effect, image or spatial data that is implied or intended from the author of source of the audio content. Due to the physics of unprocessed audio propagation in air, which is dependent upon the frequency content and phase relationships of the source material, most audio rendering systems have an audio ‘sweet spot’ where the projections of speakers intersect. For example, in a stereo system with two speakers, the sweet spot is centered where the speakers' axes of projection (an axis perpendicular to the face of a speaker) intersect. The sweet spot occurs similarly in 5.1 sound systems, 7.1 sound systems, and other surround sound systems. Different systems may have different audio sweet spot sizes and locations, and the definition of a sweet spot may be somewhat subjective, however most audio production systems have a sweet spot and a listener's experience may depend on their location relative thereto.
The dynamic nature of an audience or a listening area can present some problems when rendering sound or video. As shown in FIG. 1, different persons may enter or leave area 52. Persons may move around from one chair to another. Furniture may move from one location to another. However, the audio or video will not intelligently and dynamically adjust itself to the listener's or viewer's new position, perhaps due to lack of sensing or detection equipment or mechanisms or limitations thereof. Persons and/or furniture may be relocated outside the audio sweet-spot of nearby stationary speakers.
As different people enter or leave a media presentation area such as area 52, the people may in turn have to adjust audio and/or video volume, intensity, balance, equalization, or other digital signal processing settings on the rendering device(s) to match their own personal preferences or the limitations of their senses. For example, one person may enter a home theatre and tune the hue of the display or projector. If that person leaves and another person enters, that person may need to readjust the audio and/or video settings to match their own physiology and perception. As another example, a person with sensitive hearing may enter a video presentation exhibit at a museum and may have to adjust the volume of the exhibit to avoid discomfort.
In sum, audio and/or video output has been statically presented and has not often been optimized dynamically to take into account observable real-world conditions and occurrences.